1. Field of the Invention
The present invention relates to an active forceps used for less invasive surgical operation and more particularly to a downsized high-stiffness active forceps.
2. Related Art
In the prior art, most of the active forceps in master-slave-type robot for less invasive surgical operation (particularly for endoscopic surgical operation) has been wire-driven, since it is relatively easy by driving it with wire to realize a downsized mechanism changing orientation by a driving force transmitted from an actuator positioned at the bottom to the tips of forceps.
However, a wire-driven forceps has been used for endoscopic operations such as suture of blood vessels with no requirements of strong force, since it is difficult to transmit a strong force to the tips of the forceps even with a high driving force of the actuator, due to the poor stiffness and durability of wire likely to be stretched or cut.
When an active forceps is used for evisceration, for example, an actuator with strong driving force efficiently transmitted to forceps tips of high stiffness is required to hold organs at the forceps tips. Therefore, the above conventional wire-driven active forceps have been inappropriate for evisceration.
An object of the present invention is to provide an active forceps capable of solving the above problem advantageously. An active forceps of the present invention comprises: a forceps tip part having a tip supporting member to support a forceps tip at a center section with a plurality of arms laterally projected therefrom, and a plurality of tip side advancing and retreating members connected at a front end with the plurality of arms respectively oscillatable while connected to one another relatively movable in directions toward front and rear ends; and a forceps bottom part having a plurality of bottom side advancing and retreating members each integrally coupled to the plurality of tip side advancing and retreating members, while connected to one another relatively movable in directions toward front and rear ends to constitute a link mechanism together with the tip side advancing and retreating members and the tip supporting member, and a bottom frame provided with a forward and backward actuating means for moving relatively to one another the bottom side advancing and retreating members toward front and rear ends.
FIG. 1 schematically illustrates the operation of the active forceps according to the present invention having respectively a pair of tip side advancing and retreating members and a pair of bottom side advancing and retreating members. As illustrated, in an active forceps of the present invention, a plurality of bottom side advancing and retreating members 6 constituting a link mechanism together with tip side advancing and retreating members 3 and forceps tip supporting member 2 are moved by actuating means, arranged at an unillustrated bottom frame of forceps bottom 9, from the starting position as shown in FIG. 1(a) relatively to one another toward front and rear ends as shown in FIG. 1(b). In the drawings, left bottom side advancing and retreating member 6 is fixed, while right bottom side advancing and retreating member 6 is advanced upward. Then, as a result of the relative movement of these bottom side advancing and retreating members 6 toward front and rear ends, a plurality of tip side advancing and retreating members 3 each integrally coupled with those bottom side advancing and retreating members 6, while connected to one another relatively movable toward front and rear ends (up and down as shown in the drawings) are relatively moved toward front and rear ends. In the drawing, left tip side advancing and retreating member 3 stands still, while right tip side advancing and retreating member 3 is advanced upward. Caused by this, forceps tip supporting member 2 at forceps tip part 4 moves a plurality of arms 2b laterally projected from center section 2a toward front and rear ends of tip side advancing and retreating member 3 to oscillate as a whole (oscillate anticlockwise in the drawing), thereby changing orientation of forceps tip 1 supported at center section 2a (turning from the front facing position to a slanting left position in the drawing). On the other hand, when right bottom side advancing and retreating member 6 is retreated downward, on the contrary to the above, by the above actuating means (not shown), forceps tip 1 turns from the front facing position to a slanting right position.
However, FIG. 1 shows an example of 1-degree-of-freedom oscillation where right tip side advancing and retreating member 3 coupled to right bottom side advancing and retreating member 6 connects arms 2b of forceps tip supporting member 2 slidably and oscillatably, while left tip side advancing and retreating member 3 coupled to fixed left bottom side advancing and retreating member 6 connects arms 2b of forceps tip supporting member 2 only oscillatably. On the other hand, in the case of oscillation having two degrees of freedom or more with three or more of tip and bottom side advancing and retreating member respectively, a tip side advancing and retreating member coupled to a fixed bottom side advancing and retreating member may also connect arms of a forceps tip supporting member oscillatably as well as slidably,
Therefore, in the active forceps according to the present invention, the actuating means can change orientation of a forceps tip by efficiently transmitting a driving force to the forceps tip via the link mechanism, while making the forceps tip more stiff than wire-driven ones, thereby enabling application of the forceps to operations with strong force requirements at the forceps tip, such as evisceration. Moreover, the forceps tip part is mainly provided only with the tip side advancing and retreating members, the tip supporting members, the forceps tip, and connecting members, as needed, integrally coupling those tip side advancing and retreating members and bottom side advancing and retreating members. Therefore, the part of tip side from the forceps bottom part can be easily downsized with a smaller diameter, thereby enabling less invasive surgical operation e.g. in the case of evisceration with strong force requirements at the forceps tip.
Incidentally, in the active forceps according to the present invention, the forceps bottom part may have a rotation actuating means to rotate the bottom frame around a predetermined axis parallel to the direction toward front and rear ends of the bottom side advancing and retreating members together with the forward and backward actuating means and the above bottom side advancing and retreating members. In this case, it rotates the part of tip side from the forceps bottom, to rotate the forceps tip, by rotating the bottom frame around a predetermined axis parallel to the directions of front and rear ends of the bottom side advancing and retreating members together with the forward and backward actuating means and the bottom side advancing and retreating members, thereby highly stiffening the forceps tip, while permitting the part of tip side from the bottom part of the forceps to be downsized with a smaller diameter, with better degrees of freedom in changing orientation of the forceps tip.
Moreover, in the active forceps according to the present invention, the plurality of tip side advancing and retreating members and the plurality of bottom side advancing and retreating members may be fitted into one another slidable toward front and rear ends, while, in an intersecting direction, coupled to one another relatively movable toward front and rear ends by engaging grooves and protrusions. In this case, the plurality of tip side advancing and retreating members and the plurality of bottom side advancing and retreating members are coupled to one another with high stiffness, thereby highly stiffening the forceps tip in a simple construction.
Moreover, in the active forceps according to the present invention, at least either the plurality of tip side advancing and retreating members or the plurality of bottom side advancing and retreating members may be formed of high-silicon stainless steel such as silicolloy (trade name). In this case, a driving force can be transmitted more efficiently, through the affect of the extremely small friction coefficient between high-silicon stainless steel pieces.
Moreover, in the active forceps according to the present invention, the forward and backward actuating means may fix with magnet at the bottom frame one of the plurality of bottom side advancing and retreating members, while removably fitting into the rest of the bottom side advancing and retreating members to advance or retreat the bottom side advancing and retreating members. In this case, the bottom side advancing and retreating members can be easily removed from the forward and backward actuating means together with the part of tip side from the forceps bottom part, making it easy to change, wash, sterilize, etc. such part. In addition, one of the plurality of bottom side advancing and retreating members is fixed at the bottom frame, thereby enabling a smaller number of bottom side advancing and retreating members than the total number thereof to be directly moved by the forward and backward actuating means, to downsize the forceps bottom part in a smaller construction.